Weight loss is an important predictor of cancer

Unintended weight loss is the second highest risk factor for some forms of cancer, concludes the first robust research analysis to examine the association.

A team led by the Universities of Oxford and Exeter conducted the first systematic review and meta-analysis to examine all available evidence on the association between weight loss and cancer in primary care. Their study, funded by the National Institute for Health Research and published in the British Journal of General Practice, found that unintended weight loss is the second highest risk factor for colorectal, lung, pancreatic and renal cancers.

The research analysed the findings of 25 studies, incorporating data from more than 11.5 million patients in total, found that weight loss was linked with 10 types of cancer. The analysis found that unintended weight loss in people over 60 exceeded the 3% risk threshold for urgent investigation in NICE guidelines. In females over 60, the average risk across all sites involved was estimated to be up to 6.7%, and in males up to 14.2%.

Lead author Dr Brian Nicholson, of the University of Oxford, said: "Streamlined services that allow GPs to investigate non-specific symptoms like weight loss are vitally important and urgently needed if we are to catch cancer earlier and save lives. Our research indicates that coordinated investigation across multiple body sites could help to speed up cancer diagnosis in patients with weight loss. We now need to continue our research to understand the most appropriate combination of tests and to give guidance on how much weight loss GPs and patients should worry about."

Professor Willie Hamilton, of the University of Exeter, was co-author on the study. He said: "We've always known that unplanned weight loss may represent cancer. This study pulls together all the published evidence and demonstrates beyond doubt that it is important in efforts to save lives from cancer. It is particularly timely with this week's announcement of 'one-stop' shops for cancer diagnosis. These units pull together all the necessary tests under one roof – making the investigation of weight loss much more speedy and convenient for the patient."

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The paper, 'Weight loss as a predictor of cancer in primary care: a systematic review and meta-analysis', is published in British Journal of General Practice. Authors are Brian D Nicholson, William Hamilton, Jack O'Sullivan, Paul Aveyard and FD Richard Hobbs.